Measuring physiological responses of animals to environmental stressors using a microcomputer-based portable...

The microcomputer-based datalogger system described in this report provides excellent flexibility for accurate recording of signals from a variety of sensors at programmable intervals. The small size of the unit permits applications in many research situations in which physiological and microclimate records are required from unrestrained animals. Data presented from two experiments with cattle with ad libitum access to feed demonstrate the utility of the system. The high resolution and frequent measurements illustrate the fine detail of thermoregulatory responses of cattle (as represented by tympanic temperature) to sequential moderate and hot environments, the association of feeding activities with tympanic temperature at moderate conditions, and the disruptions in thermoregulatory function and feeding activities in hot conditions. A comparison of four anatomical sites (two internal, two sub-dermal) for measuring body temperature also illustrates shortcomings in using sub-dermal measures to reflect responses to dynamic ambient environments.